Heretofore, ball valves have been provided in which the ball valve member has been inserted within the end of a one piece valve body for assembly. For example, U.S. Pat. No. 3,348,805 dated Oct. 24, 1967 shows a ball valve in which a spherical ball may be inserted through one end of a one piece valve body with a seat then being inserted against the ball and secured by a locking ring. However, the seat is not spring urged against the ball.
While spring urged seats have been utilized and assembled within a ball valve body heretofore, such spring urged seats have been mounted within so-called top entry or end entry ball valves in which a removable body portion is mounted on the main body portion after insertion of the ball and seat member. For example, U.S. Pat. No. 4,658,978 dated Apr. 21, 1987 shows a so-called top entry ball valve in which an upper cover plate or bonnet is connected to the main body portion after insertion of the ball and spring urged seat within the valve body. Likewise, U.S. Pat. No. 3,281,112 dated Oct. 25, 1966 and U.S. Pat. No. 3,387,815 dated Jun. 11, 1968 each shows a ball valve in which an end body portion is secured to a main body portion after insertion of the ball and spring urged seat within the main body portion.